The objectives of this project broadly stated are to conduct complementary field and laboratory investigations of Schistosoma japonicum infections with emphasis on immune phenomena which might be correlated with clinical disease states. We propose to monitor antibody and cell mediated immune response including possibly significant associated phenomena in selected population groups living in an area where Schistosoma japonicum is highly endemic. Attempts will be made to correlate these observations with parasitologic and clinical data, with notes of fluctuation or changes over a five year period, and to assess if possible, the degree to which the immune phenomena contribute directly to the pathology of the disease. The role of immune renal pathology, autoimmune reactions, antiglobulin antibody and cryoglobulins will be examined.